JPH0412122A - Fuel collision diffusion type engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuel impingement diffusion type engine in which fuel injected from a fuel injection nozzle directly impinges on a protrusion provided within a combustion chamber.

[Conventional technology]

Conventionally, engine combustion chambers are typically of the direct injection type and the pre-chamber type.

A direct injection combustion chamber achieves mixing of fuel and air by the injection energy of fuel injected from a fuel injection nozzle and the swirl and squish flow formed within the combustion chamber to form a flammable mixture. However, the direct injection combustion chamber has the problem of reduced intake efficiency due to swirl generation, and also requires the fuel injection nozzle to be pressurized to amplify the atomization and penetration force of the fuel. However, it has to be configured to have a high injection rate, resulting in a complicated structure.

Further, in the pre-chamber type combustion chamber, a high stool formed in the pre-chamber achieves mixing of fuel oil droplets and air to form a flammable air-fuel mixture. The pre-chamber type combustion chamber has the problem that a high swirl is formed in the pre-chamber, and the total heat transfer area of the main chamber and the sub-chamber increases, increasing heat loss. There is a problem in that the aperture loss due to the communication hole that communicates with the chamber increases.

Therefore, in order to solve the above problems, we developed a direct injection collision diffusion stratified air supply system that uses collision jets of fuel.
An engine with a 03KA type combustion chamber is disclosed.

This 03KA type engine has a recess formed in the piston, that is, a collision part protruding from the center of the bottom of the cavity, a concave combustion chamber is formed around the collision part, and liquid fuel injected from a fuel injection nozzle is transferred to the collision part. The collision effect of the fuel jet on the collision part causes diffusion and atomization of the fuel starting from the collision surface, thereby achieving good mixing of the fuel and air. In an engine having a combustion chamber as described above, the fuel injected from the single-hole nozzle of the fuel injection nozzle collides with the flat collision surface of the collision part of the piston head and is dispersed in a disk shape, and then the fuel is generated by the rise of the piston. While the fuel is pushed down into the cavity by the squish flow, the fuel and air are mixed to form an air-fuel mixture.

Further, Japanese Patent Application Laid-open No. 120815/1983 discloses a fuel injection type internal combustion engine with external ignition. The fuel injection internal combustion engine with external ignition has a cavity formed on the top surface of the piston, a protrusion on the inner wall surface of the cavity, a collision surface with a heat insulating structure formed on the protrusion, and a cylinder head. Most of the fuel is injected toward the collision surface from the fuel injection valve, forming a richer mixture region than other regions in the protrusion layer, and the ignition device is positioned within this rich mixture region. The ignition device ignites the air-fuel mixture during ignition. The fuel-injected internal combustion engine has the above-described structure, which prevents non-king from occurring, enables a high compression ratio, improves thermal efficiency, and improves fuel consumption.

Furthermore, Japanese Patent Application Laid-open No. 139921/1983 discloses an internal combustion engine using a fuel collision reflection diffusion combustion method. The internal combustion engine uses a nozzle to inject and collide a fuel jet onto the piston surface or into the cavity, and uses the reflection-diffusion effect on the collision surface to measure the diffusion distribution and mixing of the fuel throughout the cavity starting from the collision part, rather than relying on swirl. This method uses skin flow to increase air utilization and shorten the combustion period, and the collision part is made of heat-resistant and wear-resistant material such as ceramic material, and the collision part is mounted on the top surface of the piston or inside the cavity. This is what I did.

Furthermore, a direct injection spark ignition multi-fuel internal combustion engine disclosed in Japanese Patent Application Laid-open No. 1710/1983 has a spray angle from an injection valve of mm.
Then, the main fuel jet is made to reach the piston cavity near the bottom dead center of the piston, a premixed air mixture is formed in the cavity, and a stratified air supply is created with an air layer formed outside the cavity.

[Problem to be solved by the invention]

By the way, in an engine using a piston equipped with the above-mentioned 03KA type combustion chamber, the collision surface on which the fuel injected from the single-hole nozzle collides is a flat collision surface of the piston head, and the fuel collides with the flat collision surface of the piston head. However, due to the upward stroke of the piston, a squish flow is generated into the combustion chamber, and this squish flow creates a thin film disc-shaped mixture of fuel and air to improve combustion conditions. It is. However, in order to reduce the generation of NOx,
If the injection timing of the fuel injected from the fuel injection nozzle is delayed, the squish flow will be weakened due to the reverse squish flow generated in the combustion chamber, and good mixing with the fuel jet will be impaired.
There is a problem that deterioration of combustion cannot be avoided.

Furthermore, the fuel injection internal combustion engine disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 63-120815 has a collision surface with a heat-insulating structure to promote vaporization of methanol, but it can solve the same problem as above. It's not a thing.

In addition, the squish flow is said to be weakened due to the reverse squish flow, similar to that disclosed in the above-mentioned Japanese Patent Application Laid-Open Nos. 62-139921 and 1988-1710. No measures have been taken to address the problem.

The purpose of this invention is to solve the above problems,
In order to generate a mixture between the injected fuel and air by delaying the injection timing in the cavity formed in the piston head, that is, the combustion chamber, and achieve good combustion, the piston head and cylinder head are designed to create a passage that guides the squish flow in the opposite direction. A protrusion formed with a lower surface and having a flat surface is disposed inside the combustion chamber, and fuel is injected from a fuel injection nozzle onto the flat surface, and the injected liquid fuel collides with the coating to form a uniform disc-shape. The flow direction of the air flowing into the combustion chamber in a skinsch flow through the guide passage and the fuel injection direction of the fuel diffused and injected in a disk shape are made to intersect in a nearly perpendicular state to promote mixing and fuel injection. Even if the injection timing of fuel from the nozzle is delayed, it avoids the phenomenon where the squish flow is weakened by the reverse squish flow, reduces the occurrence of No. 1, performs good combustion, and prevents the emission of unburned fuel or intermediate products. It is an object of the present invention to provide a fuel impingement diffusion type engine.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention includes a combustion chamber formed at the throat of the piston, a protrusion provided at the substantially central bottom of the combustion chamber,
A fuel injection nozzle attached to a cylinder head that opens a nozzle facing the protrusion, a flat surface formed on the top surface of the protrusion that causes the liquid fuel injected from the nozzle to collide with the fuel injection nozzle, and a flat surface formed on the top surface of the protrusion that causes the liquid fuel injected from the nozzle to collide with the fuel injection nozzle, which is injected into the combustion chamber from the bottom surface of the cylinder head. The present invention relates to a fuel impingement-diffusion engine having a protrusion that can protrude into the air and guide a squish flow to change the direction of the squish flow.

Further, in this fuel collision diffusion type engine, the protruding portion is in a state of protruding into the combustion chamber at the piston top dead center,
The protrusion and the peripheral wall of the combustion chamber form an annular conical passage.

Furthermore, in this fuel collision diffusion type engine, the injection timing of the fuel injected from the fuel injection nozzle is delayed.

[Operation] The fuel impingement diffusion engine according to the present invention is constructed as described above and operates as follows. That is, in this fuel collision diffusion type engine, a protrusion is provided at approximately the center bottom of the combustion chamber formed in the piston head, and a fuel injection nozzle with a nozzle opening facing the protrusion is attached to the cylinder head.
A flat surface is formed on the top surface of the protrusion, on which the liquid fuel injected from the nozzle collides, and in particular, a protrusion that protrudes from the lower surface of the cylinder head toward the combustion chamber is inserted into the combustion chamber at the top dead center of the piston. an annular conical passageway is formed between the combustion chamber and the wall surface of the combustion chamber, the protrusion guides the squish flow to constructively change the direction of the squish flow; This causes the squish flow to flow along the wall surface of the combustion chamber, and even if a reverse squish flow occurs, the effect of weakening the flow of the squish flow due to the reverse squish flow is suppressed.

On the other hand, the fuel injected from the fuel injection nozzle collides with the flat surface in liquid form and diffuses radially outward along the flat surface to form a disc-shaped fuel thin film, but the fuel is not guided by the protrusion. The squish flow can be caused to intersect with the disc-shaped thin fuel film, thereby achieving good mixing of fuel and air and improving combustion efficiency.

Therefore, even if the injection timing of the fuel injected from the fuel injection nozzle is delayed, the squish flow is not weakened by the reverse skiff flow, and good mixing can be achieved by intersecting with the disc-shaped fuel thin film.

〔Example〕

Embodiments of the fuel collision-diffusion engine according to the present invention will be described below with reference to the drawings.

1 [ffl is a sectional view showing an embodiment of the fuel collision diffusion type engine according to the present invention, and FIG.
FIG.

As shown in Figure 1, this fuel impingement-diffusion engine is
A cylinder block 9, an intake port 6 and an exhaust boat 7 fixed to the cylinder block 9, a nozzle 3 to the cylinder, a cylinder liner 14 fitted into a hole in the cylinder block 9, and reciprocating movement within the cylinder liner 14. It has a piston 15 that does. Intake valve 1 for 1-air boat 6
6 is disposed, and an exhaust valve I7 is disposed at the exhaust port 7. The piston 15 is made of a metal material such as aluminum, and the piston head 1 of the piston 15 is made of a metal material such as aluminum.
A cavity or combustion chamber 2 is formed therein. In particular, regarding the combustion chamber 2 formed in the piston head 1, a protrusion 5 extending upward is formed at the center bottom of the piston head. For example, a plate made of ceramic such as zirconia (ZrOl) with high heat insulation properties can be attached to the protrusion 5. The upper part of the protrusion 5 extends upward from the bottom surface of the cavity and is located below the opening 100 surface of the combustion chamber 2, that is, the top surface of the piston head 1. The top surface of this protrusion 5 is formed into a flat surface 12. This flat surface 12 constitutes a collision surface on which the liquid fuel collides.

Further, the cylinder head 3 is formed with a protrusion 8 extending downward toward the piston and facing the combustion chamber 2 formed in the cylinder 1 . This protruding portion 8 becomes an enlarged protruding portion whose lower portion has a larger cross-sectional area, and is in a state of protruding into the combustion chamber 2 at the piston top dead center. On the other hand, a fuel injection nozzle 4 having a nozzle opening 11 facing the flat surface 2 of the protrusion 5 provided in the combustion chamber 2 is attached. The fuel injection nozzle 4 consists of an injection nozzle such as a bottle nozzle, and the injection nozzle 1
The structure is such that the fuel injected from 1 collides with the center of the flat surface 12 in liquid form.

Therefore, as clearly shown in FIG. 2, the protruding portion 8 provided on the cylinder head 3 extends downward corresponding to the expansion of the cavity forming the combustion chamber 2 formed in the piston head 1, that is, the peripheral wall of the combustion chamber 2. The cross-sectional area increases in the direction, and at the top dead center of the piston, the protrusion 8 and the peripheral wall of the combustion chamber 2, that is, the wall surface 19
and form an annular conical passage 13. Therefore, the jet flow generated by the rising of the piston into the combustion chamber 2 is guided by the outer circumferential surface 18 of the protrusion 8, and the jet direction is changed as shown by the arrow, and the jet flow is directed along the wall surface 19 of the combustion chamber 2. It becomes a swirling flow. Therefore, the swirling flow of the squish flow intersects the liquid fuel injected from the injection port 11 of the fuel injection nozzle 4 at right angles S, thereby promoting the mixing of air and fuel. Therefore, even if the injection timing of the fuel injected from the fuel injection nozzle 4 is delayed in order to prevent the generation of NOx, the squish flow guided by the protrusion 8 will not resist the reverse squish flow and will continue to squish. A phenomenon that weakens the swirling flow of the flow does not occur.

The fuel collision diffusion type engine according to the present invention is constructed as described above and operates as follows.

In this fuel collision diffusion type engine, fuel injected at low pressure from a nozzle 11 of a fuel injection nozzle 4 attached to a cylinder head 3 is converted into a rod-shaped liquid fuel into a flat protrusion 5 in a combustion chamber 2 facing the nozzle 11. It impinges on surface 12 and diffuses radially outward in the form of a thin film-like disk. At this time, the squish flow generated by the rise of the piston 1 is guided by the outer peripheral surface 18 of the protrusion 8 provided on the cylinder head 3, flows into the combustion chamber 2 through the annular conical passage 13, and then combusts A swirling flow is formed along the wall surface 19 of the chamber 2 and the wall surface 20 of the projection body 5. Therefore, the squish flow intersects the disk-shaped thin film fuel in a perpendicular state to achieve good mixing, thereby ensuring a good combustion state and improving combustion efficiency.

Normally, in order to reduce the generation of NOx, the fuel injection nozzle 4
However, with the conventional combustion chamber structure, if the injection timing is delayed, the squish flow into the combustion chamber is a reverse squish flow, so the squish flow into the combustion chamber is reversed. The flow is weakened and good mixing with the fuel jet is impaired, causing poor combustion.

However, in this fuel impingement diffusion type engine, a protrusion 8 is provided on the lower surface of the cylinder head 3 to serve as a guide for changing the flow direction of the squish flow. Even if the direction of the swirling flow in the chamber 2 is changed to the opposite flow direction from the normal flow, that is, the flow from the outside part to the center part of the combustion chamber 2, and a reverse squish flow occurs, the reverse squish flow is a squish flow. The swirling flow of the fuel jet is not obstructed, and good mixing between the disk-shaped fuel jet and the air is maintained, and even if the injection timing is delayed, deterioration of the combustion state can be avoided. Therefore, the liquid fuel injected from the nozzle 11 of the fuel injection nozzle 4 collides with the flat surface 12 of the protrusion 5 and immediately
It spreads in the radial direction along the , becoming a disk-shaped film and spreading uniformly. Therefore, the fuel in this disc-shaped film intersects perpendicularly with the squish flow into the combustion chamber 2 that occurs with the upward stroke of the piston 1, promoting mixing and allowing immediate ignition and combustion.

〔Effect of the invention〕

The fuel collision diffusion type engine according to the present invention is configured as described above, and has the following effects. That is, this fuel collision diffusion type engine includes a combustion chamber formed in a piston head, a protrusion provided at approximately the center bottom of the combustion chamber, and a fuel injection nozzle attached to the cylinder head with a nozzle opening facing the protrusion. , a flat surface formed on the top surface of the protrusion that collides the liquid fuel injected from the nozzle, which can protrude into the combustion chamber from the lower surface of the throat of the cylinder, and guides the squish flow to change the direction of the squish flow. Since the projection has a protrusion that guides the squish flow and positively or forcibly changes the direction of the squish flow, the annular conical passage formed by the protrusion and the wall surface of the combustion chamber guides the squish flow. The flow is caused to flow along the wall surface of the combustion chamber and the wall surface of the protrusion to form a swirling flow, thereby suppressing the effect of weakening the squish flow due to the reverse squish flow. Therefore, even if a reverse squish flow occurs, the swirling flow in the squish flow is not weakened, so that good mixing of the spray and air can be maintained, and deterioration of combustion can be avoided even when the injection timing is delayed.

On the other hand, the fuel injected from the fuel injection nozzle collides with the flat surface in liquid form to form a disc-shaped fuel thin film, and the squish flow guided by the protrusion crosses the disc-shaped fuel film. It is possible to achieve good mixing and improve combustion efficiency.

Therefore, even if the injection timing of the fuel injected from the fuel injection nozzle is delayed, the squish flow is not weakened by the reverse squish flow, and good mixing can be achieved by crossing the disk-shaped fuel 'iR film.

Further, when the protrusion protrudes into the combustion chamber at the top dead center of the piston, the protrusion and the peripheral wall of the combustion chamber form an annular conical passage. It is reliably guided by the annular conical passage, flows from the outside to the center of the combustion chamber along the peripheral wall of the combustion chamber, avoids colliding with the reverse skinsh flow, and crosses the disk-shaped thin fuel film to form a good flow. mixed.

Furthermore, since the injection timing of the fuel injected from the fuel injection nozzle is delayed, the squish flow is not weakened by the reverse squish flow, and combustion that suppresses the generation of NOx can be performed.

Therefore, the impingement surface of the coating can always be provided with a clean impingement surface, and the liquid fuel impinged on the coating can always be well diffused radially outward along the impingement surface, and the fuel is preferably Diffuses into a thin film disc.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a fuel impingement diffusion type engine according to the present invention, and FIG. 2 is an enlarged explanatory view of a portion indicated by reference numeral A in FIG. 1- Piston head, 2-- Combustion chamber, 3- Cylinder head, 4- Fuel injection nozzle, 5 Projection, 8- Projection, 10 =- Opening of combustion chamber, 11- Nozzle port, 12-
flat surface, 13- annular conical passage; Applicant: Isu＼Jidosha Co., Ltd., Patent Attorney: So Naka Onaka

Claims (3)

[Claims] (1) A combustion chamber formed in the piston head, a protrusion provided at the bottom of the combustion chamber in the center, a fuel injection nozzle attached to the cylinder head with a nozzle opening facing the protrusion, and a fuel injection nozzle that is injected from the nozzle. Fuel collision/diffusion having a flat surface formed on the top surface of the protrusion that collides the liquid fuel, and a protrusion that can protrude into the combustion chamber from the lower surface of the cylinder head and guides the squish flow and changes the direction of the squish flow. formula engine. (2) The fuel impingement-diffusion engine according to claim 1, wherein the protrusion protrudes into the combustion chamber at the top dead center of the piston, and the protrusion and the peripheral wall of the combustion chamber form an annular conical passage. . (3) The fuel impingement diffusion engine according to claim 1, wherein the injection timing of the fuel injected from the fuel injection nozzle is delayed.